1. Field of the Invention
The present invention relates to a mobile ad hoc network and, in particular, to a duplicate detection method for a mobile ad hoc network.
2. Description of the Related Art
Wireless networks have become increasingly popular with the developments of mobility technologies and mobile devices. There are typically two kinds of mobile networks. The first is known as infrastructured networks with fixed nodes and the second is known as ad hoc networks that do not require any fixed infrastructure.
The infrastructured networks are based on the cellular concept and require an infrastructure including a fixed node, e.g. a base station or an access point (AP), such that two mobile nodes communicate via the fixed node. Typically, Global System for Mobile communication (GSM), Universal Mobile Telecommunications System (UMTS), Code Division Multiple Access (CDMA), Wireless Local Loop (WLL), and Wireless Local Area Network (WLAN) can be classified as infrastructured networks.
An ad hoc network, on the other hand, is a collection of mobile nodes forming a temporary network without the aid of any existing infrastructure or centralized administration. Mobile Ad Hoc Network (MANET) is a kind of wireless ad hoc network and is a self-configuring network of mobile nodes each acting as a router. Due to the mobility of the MANET, the mobile nodes may comprise any device capable of carrying out the desired operation. Even devices with limited resources such as computational power, memory, and battery capacity can be mobile nodes.
As described above, since a MANET is self-organized through mobile nodes without the aid of any existing infrastructure, it can be established flexibly in any situation. The mobile nodes are free to move randomly and organize themselves arbitrarily. Hence, the network topology may change rapidly and unpredictably. The mobile nodes act as hosts and mobile routers simultaneously in order to communicate with each other and relay data for other nodes. Thus, end nodes and relay nodes are not distinguished from each other. Since no central administrative node controls the network, the network management is distributed among the mobile nodes.
However, the MANETs suffers duplicate problem in that intermediate nodes generate duplicates of the transmitted packet while exchanging and relaying the data. For example, if a specific node broadcasts a packet, neighbor nodes receive and relayed the packet to their next hop nodes such that a target recipient node receives a plurality of duplicates of the packet from the intermediate nodes. Typically, a duplicate detection is performed in the application layer. In order to detect whether duplicates are received, a duplication detection application need be activated. However, activating the application layer for detecting the duplicates is inefficient and wastes power consuming. Accordingly, there has been a need for avoiding data duplication in MANETs.
In the conventional MANETs, the duplicate problem exists even in the unicast mode such that the recipient node receives duplicates from multiple intermediate nodes.